This invention relates to a method and apparatus for controlling the fluid flow rate from a pump. The method and apparatus are advantageously used to control the flow of fuel to an internal combustion engine.
The rate of flow of fluid from a pump varies with variations in the operating speed of the pump. In addition, the rate of flow of fluid from a pump varies with other factors such as changes in ambient temperature and pressure and pump wear. Since pump output is not strictly a function of pump speed, flow meters have been utilized in many control systems requiring accurate pump output information. Such a control system may be used to control a flow of fuel from a fuel pump to an engine. Of course, flow meters are relatively costly and also require a finite amount of time to provide a control signal. Other control systems are known which do not utilize a flow meter to measure pump output. However, these systems must rely upon an error signal being provided if the pump output does not achieve a desired fuel flow rate. Therefore, a delay occurs before the error is corrected.